10 Wild 'N Crazy Bike Designs (Slideshow)

TreeHugger has had a long love affair with the bicycle. It's the world's most energy efficient vehicle, and riding them cuts back on gas and carbon emissions, while promoting good health and exercise. Bicycles even appear to be recession proof. With all these things to like about bikes, various designers have been working hard to improve the two-wheeler, and have come up with some pretty wild 'n crazy ideas. Some are real, some we just wish were real. Some don't have pedals, and some don't even have two wheels.